The present invention relates to a roller clamp for regulating fluid flow through a plastic tube (hereafter referred to as roller clamp), and more particularly to a roller clamp capable of supplying a constant amount of fluid through a plastic tube by pressing a plastic tube with a roller wheel against a bottom plate having a pair of projections formed on the top of lines each extending from the lowest position of a V-shaped channel.
In a instillation assembly for supplying continuously to a patient liquid drug such as Ringer solution and liquid amino acid, or blood, a roller clamp provided in the midway of a fluid-guiding tube is widely used since the roller clamp can regulate an amount of fluid supplied to a patient.
As an example of such roller clamps, Japanese Examined Patent Publication No. 36526/1971 discloses a device for regulating fluid flow through a tube by pressing with a movable roller wheel a plastic tube inserted into a long and narrow, hollow box to deforme the tube, i.e. to change a section of the tube. Further, as an improved device of the device disclosed in Japanese Examined Patent Publication No. 36526/1971, there is disclosed, in Japanese Examined Patent Publication No. 27870/1985 which corresponds to U.S. Pat. No. 4,013,263, a roller clamp wherein a bottom plate of a long and narrow box has a crosswise section shown in FIG. 4.
In FIG. 4, a plurality of raised portions 13, which are separated from each other by a plurality of discrete valley portions 15, are formed in the left side portion and right side portion of a V-shaped channel 14. A roller wheel 21 presses a plastic tube 22 to deform the tube 22, so that both ends of the tube 22 are surely fixed by a plurality of concaved or convexed portions on the side portion of the V-shaped channel 14. Fluid passes through a deformed inner space 16 formed in the central portion of the V-shaped channel 14.
However, when dripping infusion is carried out with arranging the above-mentioned roller clamp in an instillation assembly, it has been found that the dripping number is reduced as time goes on, so that a required amount of fluid is not always supplied to a patient at a required flow velocity.
As a result of various investigation, the present inventor has found out that a supply speed of fluid can be stabilized by forming a pair of projections near a V-shaped channel as much as possible, and completed the present invention.